#ifndef _SHA1_H_
#define _SHA1_H_

class SHA1
{

public:

	SHA1();
	virtual ~SHA1();

	/*
	 *  Re-initialize the class
	 */
	void Reset();

	/*
	 *  Returns the message digest
	 */
	bool Result(unsigned *message_digest_array);

	/*
	 *  Provide input to SHA1
	 */
	void Input(const unsigned char  *message_array,
		unsigned      length);
	void Input(const char  *message_array,
		unsigned  length);
	void Input(unsigned char message_element);
	void Input(char message_element);
	SHA1& operator<<(const char *message_array);
	SHA1& operator<<(const unsigned char *message_array);
	SHA1& operator<<(const char message_element);
	SHA1& operator<<(const unsigned char message_element);

private:

	/*
	 *  Process the next 512 bits of the message
	 */
	void ProcessMessageBlock();

	/*
	 *  Pads the current message block to 512 bits
	 */
	void PadMessage();

	/*
	 *  Performs a circular left shift operation
	 */
	inline unsigned CircularShift(int bits, unsigned word);

	unsigned H[5];            // Message digest buffers

	unsigned Length_Low;        // Message length in bits
	unsigned Length_High;        // Message length in bits

	unsigned char Message_Block[64];  // 512-bit message blocks
	int Message_Block_Index;      // Index into message block array

	bool Computed;            // Is the digest computed?
	bool Corrupted;            // Is the message digest corruped?

};

#endif
